Separable electric connection



May 24, 1938. B. E. KUNKLE 2,118,562

7 SEPARABLE ELECTRIC CONNECTION Filed March 1, 1935,

m @ZM ATTORNEYS.

Patented May 24, 1938 rA'rsNT: OFF-ICE SEPARABLE ELEGTRIC CONNECTION new n. 'Kunkle, South Bend, Ind., assigncr' o! one-hall to Florence E. Newhall, Chagrin Falls,

Ohio

Application March 1, 1935, Serial No. 8,918

2 illaims.

plug is detached, preventing their ready insertion I in the openings, and the frequent breakage of the plugportion carrying the prongs.

It is anobject'of my invention to provide a terminal device for the cord and a complementary terminal device for the timed conductors which shall avoid the objections of the two prong connections and which, on the contrary, may be readily inserted without requiring the cord memher to be in a certain position, and which shall not be liable to distortion or breakage in use.

I accomplish the above object by providing a cord plug of cylindrical form carrying a central contact and a concentric annular contact, and by providing a socket having contacts adapted to engage the two contacts of the plug irrespective oi the axial position of the plug in the soclret. This enables the plug to be inserted in any position in a wall receptacle for instance, and there is no necessity for visual inspection of openings in the receptacle.

My plug has an annular insulating sleeve which carries an annular contact on its interior so that it is thoroughly protected. The socket member has two concentric insulating sleeves with the contacts on the inside and outside of the inner sleeve. The result is that when the plug is in-' serted. the inwardly facing annular contact oi the plug engages the outer socket contact and the central contact of the plugengages theinner socket contact.

' My invention adapts itself to a sturdy construction not liable to breakage or distortionand thoroughly insulated. The socket may, for instance, be a fixed wall or floor receptacle or may be in the form of an adapter formed on one face to receive the plug and-on thecther with'prongs or screw thread to engage present receptacles or I lamp sockets, as desired.

Qther characteristics of my separable electric connection, and advantages resulting therefrom, will. become apparent from a detailed description hereinafter given of preferred embodiments illustrated'inthe drawing hereof.

In the drawing, Fig. 1 is aside elevation, partly ing a head ll.

of insulating material, as hard rubber or Baketension broken away; of the complete device with the plug inserted in a wall orfloor receptacle; Fig. 2 is a face view of the same, being a section through the contact carrying sleeve of the plug, as indicatedby the line 2-2 in Fig. 1; Fig. 3 is a. face view of the socket member and a supporting bar therefor, as employed in a base or wall receptacle;

Fig. 4 is a separated diametric sectional view of the plug and socket parts; Fig. 5 is a diametric section of an adapter having two prongs to en- Rd able the use of my plug with the present floor and wall receptacles; Fig. 6 is a diametric section of an adapter having a screw sleeve enabling the use of my plug with the present lamp socket.

As shown particularly in Fig; 4, the body of my 16 plug comprises a hollow cylindrical sleeve Ild hav- This maybe an integral member lite. Rigidly mounted at the center of the-head is a metallic post it forming the central contact, 20 and on the inner face or the sleeve it near its free end is a metallic sleeve 33 forming the annular contact. Each of these contacts is metallically connected with binding screws on the outer face of the head Ill. As shown, the central con- 25 tact it has at its outer end a lateral bar it extending beneath the head of a screw it threaded in a nut ll embedded in the head. Similarly, the metallic sleeve it has a longitudinal metallic exit, terminating in a bar it which extends to beneath the head of the binding screw 20, threaded in a nut 2i embedded in the head.

The construction described enables the ready attachment of the terminals'oi the cord to the terminals. of the plug- The cord is illustrated as atill in Fig. 4, and its two conductors a, a,

. stripped of their insulation, are clamped bythe screws it and 2d against the two contact bars l5 and It. 1

The connections from the cord to the plug are to protected by a suitable insulating cap 30. This can may be a cylindrical sleeve having a head it with a central opening for the passage of the cord,

and may have on its inner annular face a screw thread 32 engaging a thread it formed on the i5 exterior of the sleeve it. By unscrewing the cap from the sleeve intothe position illustrated in Fig. 4, the cord conductors may be readily atknotted or bound, as indicated at a2 in Fig. 4 so that any pull on the cord is taken by the head 3| of the cap and not by the binding screws. II desired, instead of screwing the sleeve 30 of the cap onto the sleeve III as shown, such sleeve 30 might be an integral portion of the sleeve ll but in larger diameter, as indicated, and the head ll might be'removable from the sleeve 30, being suitably attached in use by a screw thread or other means.

The socket member of my separable connection, illustrated in each of the figures, comprises two concentric spaced sleeves 40 and ll of insulating material and a suitable head portion 42 connecting the sleeves at the inner end thereof.

The annular space 43 between the two sleeves is of somewhat greater radial dimension than the thickness of the sleeve lB-wlth its contact l3, while the bore of the sleeve 40 is larger than the exterior of the post l2; Accordingly, the plug may be readily inserted into the socket.

The two contacts of the socket are carried on the inner and outer wall of the inner sleeve 40;

- that is to 'say,'there is a metallic spring contact 50 extending longitudinally along the inner wall of thesleeve M3, and an outer contact, which extends longitudinally along the outer side of the sleeve 40. These contacts are electrically connected. through-the socket head with binding screws or other conductors, ashoreinaiter explained.

The contacts 50 and 60 are bowed inwardly and outwardly to some extent,"as shown'in Figs. 4, 5 and 6, to make a good spring contact with the post l2. .and annular conductor II of the plug. It will be seen from Figs. -2 and 3 that these contacts 50 and 60 are in substantially the same radialplane' -that is, directly opposite each other on the same side of the axis of the plug-s that the lateral pressure of the contact 50 against the post I! tends to pull the plug in the direction to make a tight connection between the sleeve I3 and the contact 60. Similarly, the contact 60 tends to push the plug laterally in the opposite direction to cause a firm contact between the post l2 and the contact 50. Accordingly, though the plug sleeve may be suiliciently smaller in external diameter than the internal diameter of the socket sleeve 4| to allow very easy insertion, there is still a tight contact when the plug is pushed into final position.

The sleeve 40 preferably terminates a short distance back of the plane defining the end of the sleeve 4|, so that there is a large circular shallow recess extendingcontinuously across the inner face of the outer sleeve. When placing the 'plug in position it is only necessary that the .vent inadvertent displacement of the plug.

The description so far given of the socket applies to such socket whether embodied asa fixed receptacle or as an adapter suitable for separable attachment to a1present wall receptacle or lamp socket, the only material difference being in the means for supporting the socket and in the electric connections to the two contacts 50 and 60.

In case of the fixed receptacle of Figs. 2, 3

and 4, the contact 50 turns outwardly in the form tends outwardly in the form of a bar GI, and is then bent along the outer side 01 the sleeve at- 62. Binding screws 53 and 63 pass through the portions 52 and 62 of these contacts and are threaded in nuts embedded in the sleeve 4|, as indicated. by the nut 54 in Fig. 4. The bar portions 5| and SI of the contacts lying on the outer face of the head 42 of the socket may be protected by an insulating disc 10, secured to the socket by screws 1| These same screws may secure a supporting bar to the base of the socket.

The supporting bar 15 is shown in Fig. 1 as made of stirrup form to provide straight portions in a plane a short distance behind the plane of the open end of the socket. These straight portions have slots 16 by which the bar may be attached to the fixed wall box 11 in the usual manner. The supporting bar I5 has threaded openings 18 for the reception of screws 19 holding in place a cover plate 80 which hasa round opening through which the sleeve ll slightly ing bars 5i and BI, and accordingly the binding screws 53 and 63 are out of the range both of the supporting bar and the walls of the box 11 parallel with the'edges of that bar. The cavity of the box, therefore, need not be materially wider than the external diameter of the socket.

To enable the socket to be used as an adapter in place of the present two-prong plug, I may embody it in the form shown in Fig. 5. Here the insulating member having the two sleeves 40 and Ii. and head 42 is just the same as heretofore described, but the inner contact 50 terminates in a flat portion 55 on the outer face of the head 42, while the outer contact 60 terminates in a fiat portion 85 at the inner end of the annular space 43. 'Suitable screws 90 and Si connect these flat portions respectively with prongs 92 and 93 positioned in correspondence with the present twoprong plugs. This construction enables the socket member to be readily mounted on the exterior of the present installations in place of the present two-prong plug, and may be left in-that position suitable for the reception of the cord plug III.

In Fig. 6, I have shown the same socket construction with sleeves 40, 4i and a head 42 and contacts 50 and 60, but the socket is embodied in an adapter suitable for mounting in an ordinary lamp socket; that is to say, there is an extension of'the head 42 in the form of a boss 45 .in which is mounted a central post 95 extending axially from a central contact 96 and at its inner end secured by a nut to the contact 50, while on the outer side of the boss 45 is a screw threaded metallic sleeve 91, the' upper end of which is connected to an extension 98 of the external contact 60. This device may be mountedjn a lamp socket, in the same manner as an ordinary lamp,

and is then in position to receive the plug l0 heretofore described. 6

It will be seen from the above description that the socket member of my separable connection without change in the body thereof and with only I slight changes inthe electric connections may be embodied as a fixed socket or as an adapter for difierent mountings. When in place, the

socket provides a comparatively large available the electric connections are thoroughly insulated when the plug is being installed, all metallic parts thereof become inaccessible within the socket before the plug establishes electric connection; when it is in place all parts are entirely housed in insulating materials.

I claim: I

1. The combination of a socket member, comprising a comparatively small sleeve, a comparatively large concentric sleeve, and a connecting head, all of insulating material, bowed spring contacts with their extremities/lying respectively against the inner and outer sides of the smaller sleeve, said contacts being positioned opposite each other in a common radial plane on the same side of the sleeve axis and connected with conductors outside of the sleeves, and a plug having a sleeve adapted to enter the space he tween the two sleeves of the socket and provided with a central contact adapted to engage the contact within the inner socket sleeve and an annular contact'on the interior of the plug sleeve adapted to engage the contact on the outside of the inner sleeve of the socket.

2. In a separable electric connection, the combination of a socket member having a pair of concentric insulating sleeves, terminals lying respectively against the inner and outer wall of the inner sleeve and located directly opposite each other in a common radial plane with reference to the axis of the inner sleeve, and on the same side of said axis, at least one of them being in the form of a spring reacting on the sleeve in a manner to exert pressure in a radial direction, and a contact plug having an insulation sleeve adapted to enter the space between the two sleeves of the socket member, said plug having a central metallic post adapted to engage the inner contact in the socket and having an an- 

